Method of preparation of a continuous film coating



Au 11, 1942. 'D. E. KING 2,292,569

METHOD OF PREPARATION OF A CONTINUOUS FILM COATING Filed Nov. 22, 1937 2,292,569 F rmmzrron or A conrmm .oUsrnM COATING l 1 Mia-mob u DavidE. King, Chicago, 11]., a n 001mm bian Bank Note linois company a corporation 0! Il- ApplicationNovember 22, 19 37, S erial No.'-1'l 5,908

" 1 claim. ,(ci. 101-170) This. invention relates to. coatings andthe method of preparation. thereof and more'par- -ticularly to a'continuous filmcoating. especially adapted for usein'a decalcomania transfer.

.. preparation of a water impervious coating in an integral layer;.still another feature is the pro- ;duction 'of' an improved decalcomania transfer which is extremely difficult to" remove or counter- .feit; a further feature is the production of a destruction once it has been appliedpaper. At the same timethe transfer body may 7 be made. sufliciently thin and fragile for certain purposes tomake diflicult its removal'without Heretofore, I transfer bodies have been of print of the water resistant material. In

' order to produce a body of suiiicient substance transfer; body. for decalcoxnania stamps by ,a simpler and more economical methodithan has heretofore been known; other features and advantages will "be apparent from the following specification and drawing, in which:

Fig. 1 is a diagrammatic representation. of an intaglio. plate; Fig. 2 is a detail plan -view, .of a

portion-"of the plate; Fig. 3 isfa sectionalyiew taken alongjtheline 3' o'fj Fig-2; ,Fig .4' is a side elevational view ofJa decalcomania transfer and Fig. 5 is a side elevational view' of another positions and is,'of course, useful for many pun to,,-allowtransfer without'injury it h'asbeen pared by making a letter press or lithographtype necessary to print the material in several consecutive layers. Naturally, this'is a slow and" tedious process. I have found that a relatively-thick transfer" body may be .easily' and quickly deposited .by

means of an, intaglio printing pressqfl At the; same time the thickness may be carefully, con-, trolled- By means of an intaglio plate a" con}.

siderably greater quantity ofink can'be easily deposited. It is preferable to use a special type. of intaglio plate as illustrated in Figs'gl, 2'and 3 in order to obtain the best results. I

The press or plate is shown in the form of a flat plate l0 although a cylinder may of course be used. Covering theIsurface of the cylinder are etched recesses H. -The etching-- may be done by the conventional 'process'used e for intaglio plates. W. ,i

The principles of operation are analogous in 1 ing may consist of any of avariety of com- 1 I poses. For instance, it may be use'd as the trans- I fer body in .decalcomania transfers; for the 10- ,calized applicationof a thick coating of .varnish or lacquer to obtain variousresults such asia gloss at desired; areas, greater depth of color at T desired area's, obliteration of previously printed or pictured areas, or a greater water or yapor" proofness at desired areas; or, for. the localized application of an adhesive at desired areas. It

many respects to those used in gravureprinting. f

It is desirable, 'howevery'to vary the size and v that larger recesses with,'afluniformfidepth are in decalcomaniatransfers serves as an. excellent t illustration of the method-of operating the process and of the factors which must be con sidered in producinga satisfactory product.

. Decalcomania transfers'consist essentially of .a water resistant transfer body joined by a water soluble adhesive to a base, usually made of paper.

The transfer body whenthe adhesive is moispreferable for my process'since a greater amount of ink can thus be deposited; With the ordinary .gravure cylinder the transfer body produced is of the order of .0075 of an inch have been found to be entirely satisfactory. The recesses must tened is removedirom the paper and applied;

to an object. In order to permit this trans and film strength to hold it together and prebe large enough to carry the maximum quantity of the liquid coating film. The partitions must be. sufficiently thin to permitthe coating film after printing to flow together as it solidifies in fer, the body must have a sufficient thickness order to cover the open space left by the parti tion.- Such a coating is knownas a continuous i U ITED, PATENT o-FF- c f, i

tions are too thin or the recesses too deep the etching process will cause the partition to be etched away at the bottom. And more important, flooding will occur, the liquid deposited flowing beyond the limits of the area covered by the plate and causing the formation of a ragged ft is also necessary in obtaining a relatively sharp outline at the edge of the film while still causing coverage of the space left by the partitions that an ink or liquid having a suitable composition be chosen.

The ink used with a gravure process, in which the etching is very fine, has too low a viscosity for my purpose and will leave a ragged edge on the transfer because of its free flowing qualities. n the other hand, inks used in letter press printing will not flow freely enough to cover spaces left by the partitions and also do not flow freely into the etched plate, In addition, a fluid which, when dry, forms a body with a high fllm strength may be of course, highly desirable. The use of a suitable solvent which will allow the ink to dry quickly is also desirable.

I have found that a fluid with a nitrocellulose base serves to make a product with a high film strength and when mixed with other suitable ingredients gives the other desirable properties mentioned. The ink should contain in addition, a plasticizer, such. at tricresyl phosphate or dibutyl phthalate, a pigment, if desired, and a solvent, such as a mixture of alcohols and esters. The following composition has been found to be particularly efl'ective:

15-20% nitrocellulose fhalf-second cotton 6-896 di-butyl phthalate pigment 65-75% solvent mixture of- Parts Ethyl acetate 30 Butyl acetate 35 Butanol 15 Toluol 20 with the components being mixed in such proportions as to total 100%.

Other suitable compositions are the following:

(a) Mix 2 pounds of casein (muriatic), with 6 pounds of water. Cook the mixture at 60 C. with 90 grams of trisodium phosphate, 22% grams of borax and 36 cc. of phenol. When cool grind into the .mixture four pounds of pigment and 3 pounds water. (b) A chlorinated rubber such as Pliolite is mixed with a suitable amount of pigment and suflicient petroleum solvent added to produce the desired fluidity in the mixture.

Thus it may be seen that the area and depth titions between the recesses, and the composition of the fluid or ink are factors which must be considered in accomplishing a satisfactory result.

In preparing a decalcomania transfer in accordance with my invention a coating of a water soluble adhesive I8 is placed on a base ll usually made of a water-leaf paper. Upon the adhesive is printed with the cylinder ll transfer body l8 which in turn serves as a base for a printed design is. A single layer transfer body is usually sufllciently thick when prepared by this method, although if desired one or more additional layers may be added. Such a transfer body will normally have a thickness between .0005 and .002 of an inch, for many purposes about .001 of an inch.

If a transfer to be applied to the inside of a glass surface is to be prepared, a simliar process may be followed resulting in a product as illustrated in Fig. 5. A base 20 is joined to a transfer body 2| by an adhesive 22. A printed design 23 on the transfer body is covered by a water soluble adhesive 24. The second adhesive is used in applying the transfer to the glass surface after which the baseis moistened and removed.

Transfers prepared in accordance with my invention are particularly useful as revenue stamps. The thickness of thetransfer body in this case must be carefully controlled, being thick enough to allow ready application without injury and thin enough to prevent removal and replacement. For such stamps it is also preferable to engrave the desgin onthe surface of the transfer body, thus making counterfeiting much more difficult.

The foregoing detailed description has been given for clearnessof understanding only, and no unnecessary limitations should be understood therefrom, but the appended .claim should be construed as broadly as permissible in view of the prior art. a

I claim:

The improvement in the art of making by a single printing operation a flexible decalcomania transfer fllm having a thickness of the order of from .0005 inch to .002 inch and capable of being removed from a disposable support without serious danger of tearing or disintegration, which consists in charging a liquid having a solids content and viscosity materially, greater than in the case of an ordinary photogravure printing ink, into the cells only of a gravure printing surface having a printing area corresponding in size to the area of the desired film, the cells of which surface each have a transverse dimension of approximately .03 inch, a depth of approximately .015 inch and are separated from each other by partitions of the order of .0075 inch in width, transferring said charges to a disposable support, permitting said charges to coalesce into a unitary liquid body,and drying said body.

DAVID E. KING. 

